add buttons(from code) on the Navigation Controller and make them disappear

问题

I have added a button from the code above "view controller":

@implementation HBViewController
.....
.....
.....

- (void)viewDidLoad
{
    [super viewDidLoad];
    okButton = [[UIBarButtonItem alloc] initWithTitle:@"Ok" style:UIBarButtonItemStyleBordered target:self action:@selector(okayButtonPressed)];

    [self.navigationItem setRightBarButtonItem:okButton animated:NO];

}

- (void) okayButtonPressed{
NSLog(@"you pressed ok");
}

...But how can I hide the button?

回答1:

self.navigationItem.rightBarButtonItem = nil;

回答2:

            //to disable

        self.navigationItem.rightBarButtonItem.enabled = NO;

            //to hide - hide means setting nil will remove that button

        self.navigationItem.rightBarButtonItem = nil;


            //if u want to show again then create and assign new button again

        okButton = [[UIBarButtonItem alloc] initWithTitle:@"Ok" 

                  style:UIBarButtonItemStyleBordered

                  target:self action:@selector(okayButtonPressed)];

        [self.navigationItem setRightBarButtonItem:okButton animated:NO];

回答3:

Just set it nil

[self.navigationItem setLeftBarButtonItem:nil animated:YES];

来源：https://stackoverflow.com/questions/10718686/add-buttonsfrom-code-on-the-navigation-controller-and-make-them-disappear